In which of the following situations can one consider that the seller does not retain a significant risk of ownership? (a) For a retail sale, refund is offered if the customer is not satisfied. The...

In which of the following situations can one consider that the seller does not retain a significant risk of ownership? (a) For a retail sale, refund is offered if the customer is not satisfied. The seller can reliably estimate future returns and recognizes a liability for returns. (b) The entity retains an obligation in case of unsatisfactory performance not covered by normal warranty provisions. (c) The receipt of the revenue from a particular sale is contingent on the derivation of revenue by the buyer from its sale of the goods. (d) The goods are shipped subject to installation, and that installation is a significant part of the contract, which has not yet been completed by the selling enterprise or on its behalf.